1. Angle Pair Relationships
Section 1.6

2. Definition
Two angles are vertical angles if their sides form two pairs of opposite rays.
The lines make a perfect
Letter X.
1 and 3 are vertical angles
2 and 4 are vertical angles 1 2 3 4

3. Vertical Angles Vertical Angles are congruent (have an equal measure)!1 2
1  2

4. Definition
Two adjacent angles are a linear pair of angles if their uncommon sides are opposite rays.
What measure does a linear pair always have to add up to? 1 2
1 and 2 are a linear pair of angles.

5. Examples Are 2 and 3 a linear pair? Are 4 and 3 a linear pair?
Are 1 and 3 a vertical angles?
Are 2 and 1 a linear pair? 2 3 4 1

6. Examples 1 What are these two angles ? Write the equation.
Solve for x.
(3x + 5)°
(x + 15)°

7. Examples 2 What are these two angles ? Write the equation.
Solve for x.
(7x + 5)°
(x + 71)°

8. Complementary Angles
Angles are complementary when two of them form a 90° angle.
They can be adjacent or nonadjacent.
Draw an example of each below.

9. Complementary Angles
The two small angles add to 90°.

10. Supplementary Angles
Angles are supplementary when two of them form a 180° angle.
They can be adjacent or nonadjacent.
Draw an example of each below.

11. Supplementary and Linear Pairs of angles
Both types add up to 180° 5 6
5 + 6 = 180°

12. 2.2 HW